Let me preface my comments by saying I have no major issues with The Force Awakens, and I love The Last Jedi. However, The Rise of Skywalker was a mess that tried to backpeddle The Last Jedi and ended up neither fish nor fowl.

To that end, I liked Rey having no parents of significance in The Last Jedi, because it took away this idea that to be strong in the Force, you have to come from a certain lineage. Retconning so she is the Emperor's granddaughter just felt unnecessary, not to mention repetitive, and entirely lacking in the dramatic weight of Vader's revelation to Luke.

To your second point, I don't necessarily mind this tweak, though I don't have the same issue with Luke being momentarily tempted by the dark side. The idea that he would never be tempted by the quick and easy path ever again post Return of the Jedi seems unrealistic in any case.

I completely agree with point three. In the third film, I'd have had Finn go to where First Order Stormtroopers are “harvested” and have him lead an uprising against the First Order (I wouldn't have brought back the Emperor or any of that nonsense). I would have also revealed that Finn is Force sensitive in much more major way, and I’d have had him receiving a certain amount of training from Rey as well.